Rock drilling apparatus



F. E. slNcLAlR ROCK DRILLING APPARATUS Jan. 27, 1942.

Filed May 29, 1955 2 Sheets-Sheet 1 w Q gk @n ww xv W 1. E w ww.. .I lmw a. .Si @.M Alma@ @uw LW HHM. Lw uw 4%@ ,y A nl M um M, 1 0. 1F00 www@a. M@ .@mw .QN d. 1@ Mum m. .fw s

Jan. 27, 1942. F. E. slNcLAlR ROCK DRILLING APPARATUS Filed May 29, 1935U 2 Sheets-Sheet 2 w r ,lll 202 w iwal-MM,

Patented Jan. 27, 1942 Frank. Sinclair, Claremont, N, H., assignor toSullivan v.Machinery Company, a corporation of MassachusettsAppiicauamay 29, 1935, serial No. y24,066 3s claims.y (o1. c55-45) Thisinvention relatesto rock' drills, 4and more particularly to improvementsvin automaticfeeding means for a hammer rock. drill of the mounteddrifter type.

An object of this inventioni is to provide an improvedv automatic drill'feeding means. An-

other object is toprovide an improved automatic feeding means actuatedandcontrolled bythe vibratory actionset `up within the drill hammermotor during operation ofthe latter and having embodied thereinimprovedy reversing means whereby the direction offeed of the hammermotor may be reversed at will.- Yet another ob-r ject is to provide animproved automatic drill feeding means having embodied' therein improvedmeans for regulatingfthe rate of feed. VVA still further object is toprovide an improved automatic feeding means controlled by the vibratoryaction set up within the drill hammer motor during operation thereof andhaving embodied therein improved means for-"modifying the intensityvofthe vibratoryv action cf'the hammer motor transmitted to the feedingmeans'whereby the rate of feed may be varied. These and 'other objectswill, however, hereinafter more fully for purposes of illustration oneform which the invention may assumefin practice.' In these drawingsfFig. 1 isa side elevational view, withparts shown inlongitudinalvertical section, showing a drifter type rock drillembodyingth'eillustrative form of the improved automatic feedin-gvmeans; Fig. 2is an enlarged longitudinally extending vertical sectional view of theimproved feed effecting and controlling means.I e

Fig. 3 is a cross sectionalviewtakenon line 3--3 of Fig. 2. i

Fig. 4 is across sectional view 4-4 of Fig. 2. Y

Fig. 5 isa cross -sectlonal view taken on line 5-5 of Fig. 2. y I Y Fig.6 is a cross sectional view taken on line 6-6 ofFig.2.Y v 'f Fig. l7 isa detail sectional ,taken on line view taken on line 1-1 of Fig. 2. i

Fig. 8 is a detail sectional view taken on line 3 8 of Fig. 5.

In this illustrative embodiment of vthe invention there is shown adrifter type rock drill kof the pressure fluid actuated, :hammer typegenerally comprising a guide yshell I, la hammer motor 2 slidably guidedthereon, and improved automatic feeding means generally designated 3.

The hammer'motor 2 isof an ordinary construction Vcomprising a cylinder'4 having a piston chamber 5 containing a reciprocatory hammer piston 6for delivering impact blows to the shank of a drill steel 1 suitablymounted within the motor .chuck housing 8. Interposed'between the chuckhousing 8 and the forward end of the cylinder is a Lfront head 9, whilesecured to the rear end of the cylinderv is a rear head block IDcarrying a usual throttle valve mechanism Il for controlling the supplyof'pressure fluid from a supply line I2 to the motor cylinder. Formedalong the sides of the motor cylinder are laterally projecting guides I3slidably received in longitudinal guideways I4 formed on the guide shellas is usual in a rock drill of the type disclosed. Theguide shell 'I isprovided with a usual trunnion I5 adaptedto be clamped in the saddlemounting ofa suitable support.

'Now'referring to the improved automatic feeding means 3, it ywill benoted that secured by parallel supporting rods I6 to lthe rear end ofthe guide shell is a casing I1 housing elements of the improved feedingmeans for controlling the rotation of a feed screw I3 automatically inaccordance with a vibratory action set up b-y the hammer motor duringoperation of the latter. The feed screw I8 is journaled and axiallyslidably guided at its forward end at I9 within a bracket'20 securedtothe forward end of the guide shell while the rear end of this feed screwissupported in a manner to be later described Within the casing I1, andthis feed screw threadedly engages at 2| a non-rotatable feed nut 22Acarried by the hammer motor cylinder. This feed nut is in the form ofan internally threaded sleeve non-rotatably arranged in a bore 23 formedin a depending boss 24 integral with the motor cylinder. As shownV inFig. 2, the feed screw I8 is provided with an elongated rearwardprojection 25 having its rearward extremity extending within a bore 26formed in the casing I1 and housing suitable spring mounting means forthe yfeed screw. This spring mounting means comprises spaced thrustcollars 21, 28, the former engaging the inner face` of a nut 29 threadedon the rearward extremity of the screw projection 25, and the latterabutting a shoulder 30 formed on a sleeve 3| supported on andsurrounding the screw projection 25 and supporting the thrust washers`21 and 28. Interposed between these thrust Washers is a disc-like plate32, and the adjacent faces of the thrust washers and plate are formedwith annular raceways for the reception of ball thrust bearings 33 sothat thrust of the feed screw may be taken in either of oppositedirections during its rotation. Engaging the opposite faces of the plate32 and reacting respectively against the shoulder 34 and a followerplate 35 are coiled springs 36 and 31. Engaging the outer face of thefollower plate 35 and threadedly engaged at 38 within the rear casinghead 39 is an adjusting screw 48 for varying the tension of the coiledsprings 36 and 31 for a purpose to be later described. Fixed to the feedscrew I8 and surrounding the rearward projection 25 of the latter is apair of sleeve-like members 4l and 42. arranged in end abutting relationand are held against endwise movement with respect to the screw byengagement of the forward face'of the member 42 with a collar 43 formedon the feed screw and by engagement of the rear face of the member 4Iwith the sleeve 3 I, and against angular movement with respect theretoby usual keys. It will thus be seen that the members 4I and 42 are fixedwith respect to the feed vscrew as regards both angular and longitudinalmovements. Formed externally on the members 4I and 42 are oppositelyinclined spiral grooves on screw threads 44, and these grooves orthreads are engaged by spiral vanes 45 formed internally within a pairof rotatable ratchet sleeves or wheels 46 and 41 respectively. Thesemembers are in the form of nuts engaging the threads 44, and ,arearranged within a chamber 48 formed within the casing l1 and thischamber is closed at its forward end by a detachable head 49, whileseparating the rear end of this chamber and the bore 26 is a partition5l) having an axial opening through which the rearward screw projection25 extends and which receives the rearward portion of the member 4|.

As shown in Fig. 3, the ratchet member 46 is provided with externalratchet teeth 52 with which sets of oppositely disposed reversing pawls53 and 54 are engageable, these pawls being carried by a pawl carrierring 55 fixed within the chamber 48 by a key 56. The pawls are providedwith spring pressed plungers 51 for yieldingly urging the pawls intotheir ratchet tooth engaging position. The ratchet member 41 as shown inFig. 4 is provided with ratchet teeth 58 with which sets of oppositelydisposed spring pressed reversing pawls 59 and 6I) are selectivelyengageable, the pawls being carried by a pawl carrier ring 6l fixedwithin a chamber 48 by a key E2. It will thus be seen that a reversibleratchet and pawl mechanism is provided for each of the sleeves 46, 41 sothat the direction of rotation of these sleeves may be controlled asdesired. The means for throwing the different sets of pawls intoengagement with the ratchet teeth comprises an operating ring 63rotatably mounted in the chamber 48 between the pawl carrier rings 55and 6I as shown in Fig. 2. The means for oscillating this ring 63 aboutthe axes of the members 4I and 42 comprises, as shown in' Figs. 2, 5 and'7, a cam member 64 formedon an operating shaft 65 mounted in the casingI1 and having an operating handle 56. When the cam is swung from itscentral position into the position shown in Fig. 7, the ring 63 isturned in one direction, but when the cam is swung into its oppositeposition, as indicated in dotted lines in Fig, '7, the ring 63 is turnedin the opposite direction. Formed in the ring 63 are recesses 68, 68within which project sets of lugs 69, 10 vformed on the sets of pawls53, 54 and 59, 60. When the ring 63 is in the position shown in Fig. 5,

The members 4I and 42 are the ends of the recesses 68, 68 engage thelugs on certain of the pawls, while the lugs on the others of the pawlsare released so that one set of pawls engages the ratchet teeth whilethe other set is held out of engagement therewith. It will thus beevident that the operating ring 63 constitutes means for selectivelyrendering the different sets of pawls active, thereby to permit rotationof the members 46 and 41 in either of opposite directions depending onwhich of the pawls of the sets are active.

- The mode of operation of the improved automatic feeding means is asfollows: Let it be assumed that the hammer motor is running tc actuatepercussively the drill steel and it is desired to effect forward feed ofthe hammer motor with respect to the guide shell. Reciprocation `of lthehammer piston within its cylinder causes,

due t0 its sudden reversal of direction of movement, a longitudinalvibratory or recoil action to be transmitted by the hammer motor throughthe cylinder and feed nut to the feed screw I8, this vibratory actioncausing a slight longitudinal or endwise movement of the feed screw dueto its spring mounting 32, 36, 31 on the guide shell. Since thespirallyv grooved members 4I and 42 are rigidly fixed to the feed screwthey move longitudinally therewith, and as a result the spiral groovesthereon` engage the spiral vanes on the ratchet wheels 46 and 41 toeffect, due to an opposite vinclination of the grooves, simultaneousrotation of the ratchet wheels 46, 41 in opposite directions. To effectforward feed, the operator grasps the lever 66 and swings the cam 64 torotate'the operating ring 63 into the position shown in Figs. 5 and 6,`thereby moving the sets of pawls 54 and 60 out of engagement with theteeth of their respective ratchet wheels, while permitting movement ofthe sets of pawls 53 and 59 into engagement with the teeth of theirrespective ratchet wheels. Longitudinal movement of the feed screwv inthe rearward direction causes the ratchet wheel 41 to rotate while theset of pawls 53 hold the ratchet Wheel 46 against rotation, and as aresult rotative movement in a forward feeding direction is imparted,through the spiral vane and groove connection between the elements 46and4l, to the feed screw I8. Uponlongitudinal movement of the feed screw inthe forward direction the ratchet wheel 46 freely rotates,while the setof pawls 59 hold the ratchet Wheel 41 against rotation, and as a resultrotative movement in a forward feeding direction is imparted, throughthe spiral vane and groove connection between the elements 41 and 42, tothe feed screw I8. When it is desired to effect reverse feed of thehammer motor along the shell guideways, the operator turns the lever 66to move the operating ring 63 into its opposite position, thereby movingthe sets of pawls 53 and 59 out of engagementl with the teeth of theirrespective ratchet wheels while the sets of pawls 54 and 60 arepermitted to move into engagement with the teeth of their respectiveratchet wheels. As the feed screw moves longitudinally in oppositedirections by the vibratory recoil action of the drilling motor,rotation of the feed screw I3 is effected in a reverse feed directionthrough the spiral vane and groove connections between the ratchetwheels and the members 4I and 42. The amount of longitudinal movement ofthe feed screw in its spring mounting relative to the casing I1 may bevaried at will by adjusting the screw 40 to Vary the tension of` themounting 'springs 3B, .31 jaridasa resultythe rateof Afeedin eitherdirection may be varied at"will*`regardless of the intensity ofthevibratory action set up within `the hammer motor. I

As a result of this invention it will be noted that an improvedautomatic feeding means is provided for the hammer rock drill wherebythevibratory recoil action set up within thevhammer motor by the suddenreversal of the Adirection of movement of the hammer piston operatestoeffect feeding of the hammer motorgtheopposite forward and backwardrecoil movements of the hammer motor operating to effect feed of thehammer motor in one direction. It will further be noted that by theprovision of the spring mounting for the feed screw it is possible tovary the intensity of the vibratory action transmitted to the feedingmeans by the drill hammer motor, thereby to vary the rate of feed. Otheruses and advantages of the improved Vautomatic feeding means will beclearly apparent to those skilled in the art. y

While I have in this application specifically described one form whichmy invention may assume in practice, it will be understood `that thisform of the same is shown for purposes of illustration, and that theinvention may bemodified and embodied in'various other forms withoutdeparting from its spirit or the'sco-pe ofthe appended claims.

What I claim `as new and desire to secure by Letters Patent is:

1. In a rock drill, the combination with a hammer motor within whichlongitudinal vibrations occur during operation thereof and a guide alongwhich said .hammer motor is guided, of automatic feeding means forfeeding :said hammer motor along said guide including relativelyrotatable co-acting feed screw and nut feeding elements, said feed nutelement fixed against rotation relative to said feed screw element andthe rotatable feed screw element mounted Vfor axial reciprocation, andmeans operated by the reciprocatory movement of said rotatable feedscrew element caused by the vibratory action of the hammer motor foreffecting rotation thereof relative to said non-rotatable nut elementand including elements fixed tosaid feed screw element and having spiralgrooves of opposite inclina-- tion, a ratchet and pawl devicecooperating with each of said grooved elements and eachincludinga memberhaving spiral lugs engaging the spiral grooves, axial reciprccation ofthe feed screw 'element in opposite directions effecting rotationof anelement of each ratchet and' pawl 'device due to the engagement of thespiral lugs withthe spiral grooves.

2. In ay rock drill, the combination with a hammer motor within whichlongitudinal vibrations occur during operation thereof and a guide alongwhich said hammer motor is guided, of automatic feeding means forfeeding vsaid hammer motor selectively in opposite directions alongsaid'guide including relatively rotatable co-acting feed screw and nutfeeding elements, said feed'nutr element fixed against rotation relativeto said feed screw element and the rotatable feed screw element mountedfor axial reciprocation, andmeans operated by the reciprocatory`movement of said rotatable feed screw element caused by the vibratoryaction of the hammer motor for effecting rotation thereof relative tosaidlnon-rotatable nut element and including elements fixed to said feedscrew element and having spiral grooves of opposite inclination, aratchet and `pawl device cooperating with each of said lgroovedelements-"farrdfxeach `including a member having spiral lugs Iengagingthe: spiral vg'1.fooves axial reciprocation of the feed screwelement-indpposite directions effecting rotation of an element of eachratchet and pawl device due to the engagement of the spiral lugs withthe spiral grooves, said ratchet and pawl devices being reversible andembodying reversible pawls whereby rotation of said elements of saidratchetdevices may be controlled to effect 'rotation o'f said feed screwelement in either of opposite directions.

3. Ina rock drill, the .combination with a ham- `mer motor within whichopposite longitudinal vibrations occur during operation thereof and aguide along which said hammer motor is'guided, of automatic feedingmeans actuated by the opposite longitudinal vibrations of the hammermotor for feeding said hammer motor along said guide includingrelatively rotatable co-acting feed screw and nut 'feedingelementa saidnut feeding element fixed against rotation relative to said feed screwelement and the rotatable feed screw element mounted for axialreciprocation, and a yieldable spring mounting for said feed Iscrew'element including a member fixed for movement longitudinally therewithand opposed springs actingv on said member.

4. In a rock drill, the combination with a hammer motor within whichlongitudinal vibrations occur during operation thereof and a guide alongwhich said hammer motor is guided, of automatic feeding meansfor'feeding said hammer motor along'said guide including relativelyrotatable co-acting feed screw and nut feeding elements, said nutfeeding element fixed against rotation relative to said feed screwelement and the rotatable feed screw element mounted for axialreciprocation, a yieldable spring mounting for said feed screw elementincluding a collar fixed for movement longitudinally therewith andopposed springs acting on said collar, and means for varying the tensionof said springs to vary the range of longitudinal reciprocation of saidfeed screw element.

Y5.*In a rock drill, the combination withv a hammer `motor within whichlongitudinal vibrations occur during operation thereof and a guide alongwhich said hammer motoris guided, of automatic feeding means for feedingsaidfhammer mot-or selectively in opposite directions along saidy guideincluding relatively rotatable co-acting feed screw and nut feedingelements, said nut element fixed against rotation relative to said screwelement and the rotatable screw element mounted for axial reciprocation,a pair of ratchet and pawl devices, means fixed to said feed screwelement for axial reciprocation therewith for exerting forces'tending toeffect rotation of corresponding elements of said ratchet and pawldevices respectively in opposite directions, one ratchet and pawl deviceacting to hold said feed screw element against rotation in one directionduring axial movement of the screw element in one direction and theother ratchet and-pawl device actingto hold said screw element aga-instrotation in the same one direction during axial movement of the screwelement in the opposite direction.

6. In a rock drill, the combination with a ham mer motor withinwhich'longitudinal vibrations in yopposite directions occur duringoperation thereof, of automatic feeding means for the hammer motorincluding relatively rotatable threaded feeding elements, one carried bythe hammer motor and the other element rotatable relative thereto, thelead of the threads of said elements being such that substantially noeffective rotative tendency is imparted to the rotatable elementdirectly by the longitudinal thrusts f the element carried by the hammermotor, and means operatively connected to said rotatable feeding elementand operated directly by both of the opposite longitudinal Vibrations ofthe hammer motor for automatically positively effecting relativerotation between said threaded elements ina direction to effect feed ofthe hammer motor in a forward direction toward the work.

7. In a feeding device for a rock drill, a power actuated reciprocabletoothed member, a feeding element capable of feeding motion in eitherdirection, a movement transforming mechanism associated with said memberand element including means responsive to each stroke of said member forimparting feeding motion to said element, and means forselectivelycontrolling the direction of feeding motion of said element.

8. In a drilling apparatus, the combination with a support, of adrilling motor slidable on the support having reciprocatory motionimparted thereto, of a feeding mechanism for the motor including areciprocable and rotatable element, a self locking screw connectionbetween said motor and element whereby the reciprocation of the motor istransmitted to the element and the rotation of the element in eitherdirection causes the forward or backward feeding motion of said motor,and means associated with said element operable by virtue of thereciprocatory motion thereof for effecting its rotary motion in eitherdirection.

9. In a drilling apparatus, the combination with a support, of adrilling motor slidable on the support having longitudinal forward andbackward movement imparted thereto, of a feeding mechanism for the motorincluding a screw carried by the support in self locking threadedengagement with the motor for longitudinal movement therewith andcapable of rotation for imparting feeding motion to the motor, meansdepending upon the longitudinal movement of said screw for effecting itsrotary motion, and means associated with said screw having energy storedtherein during the rearward movement of the screw, said energy beingautomatically released during the forward movement of the screw forimparting rotation thereto additional to that normally resulting fromits forward movement.

10. In a drilling apparatus, the combination with a support, of adrilling motor slidable on the support having reciprocatory motionimparted thereto relative to the support, of a feeding mechanism forsaid motor including a rotatable element carried by the support andreciprocable longitudinally thereof, reciprocation transmitting meansbetween said motor and said element including a self locking screwconnection whereby the rotation of said element in either directioncauses the forward or backward feeding motion of the motor, and meansderiving motion from the reciprocation of said element for effectingVits rotation in either direction.

able in either directionv relatively to the other for effecting theforward or backward feeding movement of the motor, and means. associatedwith said rotatable element and responsive to the reciprocatory motionthereof for effecting its rotation in either direction.

12. In a drilling apparatus, the combination with a support, of adrilling motor slidable relatively to the support and havingreciprocatory motion imparted thereto, of a feeding mechanism for themotor including a screw carried by the support in self locking threadedengagement with the motor for reciprocation therewith and capable ofrotation for imparting feeding motion to the motor, means actuated byvirtue of the reciprocatory motion of said screw for effecting itsrotary motion in either direction, and means for selectively controllingthe direction of feeding motion of themotor.

13. In a drilling apparatus, the combination with a support, of adrilling motor'on the support having forward and backward motionsalternatively imparted thereto, of a feeding mechanism for Lthe motorincluding a screw carried by the support in self locking threadedengagement with the `motor for forward and backward movements therewithand capable of rotation for imparting feeding motion to the motor, meansdepending upon the forward or backward motion of said screw forautomatically effecting its rotation, and means associated with saidscrew for selectively controlling the rate of speed of said feedingmotion.

14. In a drilling apparatus, the combination with a support, of adrilling motor slidable on the support and having a reciprocatory motionimparted thereto, of a feeding mechanism for the motor including areciprocable element carried by the support, reciprocatory movementtransmitting means between said motor and said element including a selflocking screw connection, said element being capable of feeding movementin one or the other direction for effecting a forward or backwardlongitudinal movement of the motor additional to that of itsreciprocatory motion, a helical spline and ratchet mechanism actuated byvirtue of the reciprocatory motion of said element for automaticallyeffecting its feeding movement in one or the other direction, and meansfor controlling the direction'of feeding movement of said element.

15. In a drilling apparatus, the combination with a support, of adrilling motor on the support having jars imparted thereto to move themotor back and forth longitudinally of the support, of a feedingmechanism for the motor including a nut carried by the motor, a screwcarried by the support in self locking threaded engagement with said nutfor longitudinal movement therewith and capable of rotation in one orthe other direction for effecting a forward or backward longitudinalmovement of the motor additional to that resulting from said jars, meansassociated with said screw responsive 1 to the longitudinal movementthereof for effecting its rotation in either direction, and means forcontrolling the direction of rotation of said screw.

16. In a drilling apparatus the combination with a support, of adrilling motor slidable on the support having reciprocatory motionimparted thereto, of a feeding mechanism for the motor including a nutcarried by the motor, a screw carried by the support formed with arelatively small pitch thread engaging said nut for transmitting kthereciprocatory motion of the i 212 InA a`r rock drill, the combinationwith a motor to said screw and ,preventingftlre .rotation of the screwupon axial pressure exertedthereon by said nut, said screw being capableof rotation for effecting the `feeding movement of 'the 'milton and ahelical spline and ratchet Vme'clrarzti'sm associated with saidscrewfoperable by virtue of its reciprocation .for effecting itsrotation.

17. In a drilling apparatus the,v combination with a support, of adrilling motor slidabl'e on the support having reciproc'atory motionimparted thereto, of a feeding mechanism'A for the motor including afeed element carried by said support capable of feeding motion, aconnection between said motor and element including self. locking screwthreads for transmitting 'the -reciprocation of the motor to theelement, the feeding motion of said element causing-through saidconnection the feeding motion of said motor, and a helical spline andratchetmechanism associated with said element operable by Virtue of itsreciprocation for effecting-its feeding yrho-v tion.

18. In a drilling apparatus, the combination with a support, of adrilling motor vslidable. on the support havingv a reciprocatoryr motionimparted thereto, of a feeding mechanism for the motor including a feedmember carried by the support, a connection between saidw motor andmember including self locking screw threads `for constantly transmittingthe reciprocatory motion of the former to the latter, said member beingcapable of feeding movement for `'transmitting feeding motion to saidmotor through said connection, helical spline and ratchet means actuatedby virtue of the reciprocatory 'motion of said member for effecting itsfeeding 'move-v, ment, andy spring means associated with said memberhaving energy stored therein -dufringfthe strokes of the member in onedirection, saidV energy being automatically released during rthe strokesof the feed member in the otherdirection for imparting a feeding powerthereto addi--` tional to that normally resulting from itsja'rs,

19. In a drilling apparatus, the combination with a support andadrilling motor 'slidable relatively to the support and having'recip'ro`` catory motion imparted thereto, of a feed-ing mechanism forthe motor including a 'screw carried by the support in selflockingthreaded engagement with the motor for reciprocation therewithand capableV of rotation for imparting feeding motion to the motor, andmeans for'v effecting rotation of said screw selectively` Vin oppositedirections including a llelically"tootlfl'edY member connected tor saidscrew for reciprocation with the latter, 4a cooperatinghelicallyvtoothed member, and means for precluding rotation of saidsecond mentioned'membe'r iii-one direction or the other at will Whilepermitting rotation thereof in the direction opposite that in whichrotation is precluded. n 'y y 20. In a rock drill, the combination 'withav hammer motor having a piston andv subjected toA longitudinal jars inopposite directie.ns-by,l said' piston, of automatic feeding means forthe hain-4 nier motor includingy a feed screw mountedfor' sur hammermotor in-which longitudinal Vibrations in' opposite directions occurduring operation thereof, of automatic feeding means for the hammermotor including means actuated by the longitudinal vibrations of thehammer motor for automatically effecting feed of the hammer motor-in aforward direction', said automatic feeding means including a feed screwmounted for axial reciprocation, and means movable with the hammer motorfor causing longitudinal movements of-the feed screw in oppositedirections to attend the lopposite longitudinal vibrations of the hammermotor, and means whereby the lon- 'gitud-inal movement of the feed screwAin one 'direction directly effects positive feed of the hammer motor ina forward direction while such longitudinal movement is taking place andwhereby the longitudinal movement of the feed screw in the oppositedirection also directly effects positive feed of the hammer motor in theforward direction while the last mentioned movement of said feed screwis taking place.

22. In a rock drill, the combination with a guide shell including a feedscrew reciprocablyy mounted on said shell and a feed nut supported bysaid rock drill and means actuated by the thrust ofthe nut on the screwin a rearward direction for rotating said feed screw, while the same ismoving rearwardly relative to said shell, in a direction to causerelative advance of the feed nut therealong.

*24. Inl a' rock drill, the combination with a hammer-fnotor withinwhich longitudinal vibrations in opposite directions occur uponoperation thereof, of automatic feeding means for the ham-` mer motorincluding a feed nut and a feed screw andrne'ans actuated directly bythe opposite 1ongit'udinal vibrations of the hammer motor forautomatically effecting positive rotation of the axial movement, a feednut 'carried'by said-*11am` mer motor and transmitting to said 'screw'oppon-y site longitudinal thrusts as said'pisto'n imparts opposite jarsto said hammer motor, andfmeafns0 actuated by the rearward thrusts ofthe feed v screw to rotate the same, during such rearward thrusts,relative to the feed 'nut ina :direction to advance the Vnut relative to'theScrew-lnav feeding direction.

kvor

feedA screw relative to the feed nut in a forward-feed-effectingdirection during each of the opposite longitudinal vvibrations of thehammer motor. l l

25;` In va rock drill, the combination with -a hammer'motor withinwhichv opposite longitudinal'vibrations occur during operation thereofand a guide along which said hammer motor is guided, ofi; automaticfeeding means actuated by .the opposite longitudinal vibrations of thehammer motor for feeding said hammer motor along said guide includingrelatively rotatable co-acting feed said feed screw element and therotatable feed screw elementmounted for axial reciprocation,

a yieldable spring mounting for said feed screw element includingv meansfor yieldingly holding the same, when said motor is idle, in a positionfrom which it is movable in either direction and' to'which said yieldingholding means tends to return it irrespective of the direction in whichit is longitudinally displaced, and means operatedl by the longitudinalmovements of said feed screw element for rotating the same.

26. In a rock drill, the combination with a hammer motor within whichlongitudinal vibrations in opposite directions occur during operationthereof, of automatic feeding means for the hammer motor includingrelatively rotatable threaded feeding elements of which one is heldagainst rotation, one of said feeding elements being connected to thehammer motor so that it and said hammer motor undergo longitudinalmovements together, the lead of the threads of said elements being suchthat substantially no effective rotative tendency is imparted to therotatable element directly by the longitudinal thrusts of the elementcarried by the hammer motor, and means operatively connected to saidrotatable feeding element and operated directly by both of the oppositelongitudinal vibrations of the hammer motor for automatically positivelyeffecting relative rotation between said threaded elements in adirection to effect feed of the hammer motor in a forward directiontoward the work.

27. In a rock drill, the combination with a hammer motor within whichlongitudinal vibrations in opposite directions occur during operationthereof, of automatic feeding means for the hammer motor includingrelatively rotatable threaded feeding elements of which one is heldagainst rotation, one of said feeding elements being connected to thehammer motor so that it and said hammer motor undergo longitudinalmovements together, and means operatively connected to said rotatablefeeding element and operated directly by both of the oppositelongitudinal vibrations of the hammer motor for automatically positivelyeffecting relative rotation between said threaded elements independentlyof any wedging action directly exerted by the non-rotatable element onthe other element, in a direction to effect feed of the hammer motor ina forward direction toward the work.

28. A rock drilling device comprising a fixed support havinglongitudinally extendingguideways, a drill mounted thereon and adaptedto reciprocate in said guideways, said drill having a reciprocatinghammer piston therein adapted to impart to the drill longitudinalvibrations in opposite directions, a longitudinally extending feedmember for said drill, means for coupling the feed member to the drillto adapt the feed member to vibrate in unison with the drill, said feedmember being supported on said support by means permitting limitedlongitudinal movement of the feed member relative to the support, andmeans carried by the support and responsive to longitudinal vibrationsof the feed member in both directions for moving said feed member in adirection to advance the drill. f

29. In feeding means for percussive tools, in combination, a shell, adrill casing slidably mounted in said shell, a rotatable feed screwmounted on said shell and passing through a feed nut carried by thedrill casing, said drill casing being subject to vibrations lengthwiseof said screw, the means mounting the screw on the shell being yieldableto permit limited lengthwise movement of the screw in response to saidvibrations, and means responsive to axial movement of the screw withrespect to the shell for rotating said screw in the same direction uponeach of a pair of consecutive opposite longitudinal movements thereof.

30."In combination, a drilling machine subject to longitudinalvibrations in". both directions, a support havingvfmeans includingguideways for Asupporting said 'machine land permitting longie tudinalmovement of the latter, a longitudinally extending feed screw havingconnections with both .the machine and the support, said connectionscomprising a nut carried by the drilling machine and receiving thescrew, the lead angle of the screw and nut being such that axialmovement of the nut relative to the screw through wedging action ofthenut on the screw is substantially precluded, ratchet mechanism`carried bythe support for preventing rotation of the feed screw in therearward feeding direction, the connection between the screw and supportbeing yieldable to permit longitudinal movement of the feed screwtogether with the nut in a rearward direction, and means responsive tosuch longitudinal rearwardv movement for rotating the screw in theforwardfeeding direction.

31. In combination, a drilling machine subject to longitudinalVvibrations inboth directions, a. support having means includingguideways for supporting fsaidmachine and permitting longitudinalmovement of the latter, a longitudinally extending feed screw havingconnections with both the machine and the support, said connectionscomprising a nut carried by the drilling machine and receiving'thescrew, the lead angle of the screw and nut being such that axialmovement of the nut relative to the screw through wedging action of thenut on the screw is substantially precluded, ratchet mechanism carriedby the support for preventing rotation of the feed screw in the rearwardfeeding direction, the connection between vthe screw and support beingyieldable to permit longitudinal movement of the feed screw togetherwith the nut in a rearward direction, and means` responsive to suchlongitudinal rearward movement and also to a succeeding forward movementfor rotating the screw in the forward feeding direction.

i 32. A drilling mechanism comprising a support having longitudinal-guideways, a percussive drill movably supported in saidguideways, anelongated member connected .to said drill, means mounting saidmemberkfor limited longitudinal movement on the support, an element havingthreaded connectionA with the member and held against longitudinalmovement on the support, ratchet .mechanism preventing rotation of theelement in one direction only, another element having "an oppositelythreaded connection with said member and held against longitudinalmovement on the support, and ratchet mechanism preventing rotation ofthe said last mentioned element in vone direction only, wherebyreciprocation of thewmember with respect to said elements impartsstep-by-step rotary movement to the member during each unidirectionalpass of its reciprocatory movement.

Vv33.A, rock ldrilling device comprising a support, a percussive drillslidably mounted thereon,

a vfeed screw extendingvparallel to the direction of movement of thedrill, said screw having three sets of'threads thereon, one set beingreceived within a nut carried bythe drill and the other two sets withinnuts carried by the support, said last mentioned sets of threads ofopposite hand and both ofsaid last mentioned sets of threads havingalarge leajd angle whereby longitudinal movement of the screw withrespect'to the supporti'ineither vdirection causes -rotation of thescrew, and yieldable means forresisting Vlongitudnal movement of thescrew with respect to the support.

34. A rock drilling device comprising a support, a percussive drillslidably mounted thereon, a feed screw extending parallel to thedirection of movement of the drill, said screw having longitudinallyspaced sets of threads, one set being received within a nut carried bythe drill and the other within a nut carried by the support, saidthreads being of the same hand but of different leads, yieldable meansfor resisting longitudinal movement of the screw with respect to thesupport, and means associated with the second set of threads forcontrolling the direction of rotation of said screw.

35. A rock drilling device comprising a guide shell having longitudinalguideways, a rock drill movably mounted in said guideways and subject tolongitudinal jars imparted by a piston, and a plurality of feedmechanisms supported by said guide shell, one of said feed mechanismsbeing actuated by forward jars transmitted to it from the rock drill forfeeding the drill forwardly and the other feed mechanism being actuatedby rearward jars transmitted to it from the drill for @feeding the drillforwardly, and said two feed mechanisms being adapted to feed the drilllike distances responsive to jars of like intensity.

36. A rock drilling device comprising a shell having guideways, a rockdrill movably mounted in said guideways and having a piston reciprocablein a cylinder and adapted to impart a jar to the rear end of thecylinder on one stroke and on its other stroke to strike either thefront end of the cylinder or a drill steel, depending upon the positionof the steel and the drill, a feed mechanism carried bythe shell andadapted to.

receive forwardly directed jars from the drill to feed the drillforward, and another feed mechanism for feeding the drill forward, saidlast mentioned feed mechanism operating independently of said forwardlydirected jars and both of said feed mechanisms operating during thefeeding of the drill up to the work.

37. A rock drill device comprising a fixed support, a drill mountedthereon for relative movement in a forward and in a rearward direction,said drill having a cylinder with a piston therein, said cylinder beingsubjected to successive jars in a rearward direction upon reversal ofthe direction of the piston, a feed nut carried by the drill andreceiving a longitudinally extending feed screw carried by the support,and mechanism for operating the feed screw to move the drill step bystep forwardly, said mechanism comprising means responsive to jarringmovement of the cylinder rearwardly relative to the support for causingthe feed screw to rotate to move the drill a step forwardly relative tothe screw while the rearward, jar-eected movement of the cylinderrelative to the support is taking place.

38. In a rock drill, the combination with a hammer motor within whichlongitudinal vibrations occur during operation thereof and a guide alongwhich the hammer motor is guided, of automatic feeding means for feedingsaid hammer motor along said guide including relatively rotatablecoacting threaded feeding elements, one feeding element fixed againstrotation and the other, rotatable, feeding element mounted forlongitudinal movement, and means operated by each longitudinal movementof said rotatable feeding element caused by the vibratory action of thehammer motor for effecting rotation thereof relative to saidnon-rotatable feeding element in a feed-effecting direction.

FRANK E. SINCLAIR.

CERTIFICATE OF CORRECTION.

Patent No. 2,271,026. January 27, 19LL2.

FRANK E. SINCLAIR.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,first column, line 25, for the word "on" read -or.; and that the saidLetters Patent should be read. With this correction therein that thesame may conform to the record of the case in vthe Patent Office.

signed and sealed this 21st day of April, A. D. 19u2.

Henry Van Arsc'lale,

(Seal) Acting Commissioner of Patents.

